Carbon Fiber Layup On Coaming

The cockpit rims on these boats are being finished with a carbon fiber layup. The fabric is 5.5oz twill weave from U.S. Composites. I cut an oversized piece and laid it over the coaming and cockpit opening, gently smoothing the wrinkles and puckers by hand.

After I was satisfied with the way the fabric was laying I poured a generous amount of unthickened epoxy around the rim. I worked the epoxy into the carbon fiber using a plastic squeegee and a disposable chip brush. The squeegee was used to hold the fabric from sliding while I pushed and dabbed with the brush to work the epoxy into the fabric.

Once the fabric was thoroughly saturated I laid pieces of fiberglass cloth over top of the carbon fiber and wet out the fiberglass with more epoxy. I read so many posts on the forum warning that carbon fiber should be covered in fiberglass to help contain sharp splinters and shards in case it shattered, that I became convinced it was just a ticking timebomb ready to explode at any moment and shower any unsuspecting bystanders with "Carbon Fiber Shrapnel".

Coping With The Coaming

Plastic sheeting separates the laminations from the deck

The coaming is assembled from layers of plywood, laminated together. Reading the manual and picturing the assembly I could see this was going to be one of the more challenging tasks in building these boats. I again referred to Laszlo's wood duck blog, and the technique he illustrated for assembling and installing a laminated cockpit rim seemed much easier.
Laszlo recommends putting plastic sheeting on the deck around the cockpit opening and using the boat as a jig to glue up the pieces of the coaming. The pieces will form to the proper shape to mate to the deck, but the plastic stops them from adhering to the boat. Once the epoxy cures, the whole coaming assembly can be removed, allowing easy access to all sides for sanding and shaping.  Once all the rough (very rough) edges have been smoothed the coaming can be epoxied in place on the deck. When I used this method I only had to be concerned with cleaning up the squeezed out epoxy from one glue joint, not several.

The inside rim of the cockpit rim is easily sanded

Once shaped the rim is epoxied to the deck

Very little squeezed out epoxy to deal with using this method